VirtualMachineManager: Take in EventLoopGroup directly (#367)

Sources/Containerization/VZVirtualMachineInstance.swift

@@ -76,13 +76,14 @@ struct VZVirtualMachineInstance: Sendable {
     // `vm` isn't used concurrently.
     private nonisolated(unsafe) let vm: VZVirtualMachine
     private let queue: DispatchQueue
-    private let group: MultiThreadedEventLoopGroup
     private let lock: AsyncMutex<VendedConnections>
+    private let group: EventLoopGroup
+    private let ownsGroup: Bool
     private let timeSyncer: TimeSyncer
     private let logger: Logger?
 
     public init(
-        group: MultiThreadedEventLoopGroup = MultiThreadedEventLoopGroup(numberOfThreads: System.coreCount),
+        group: EventLoopGroup? = nil,
         logger: Logger? = nil,
         with: (inout Configuration) throws -> Void
     ) throws {
@@ -91,9 +92,16 @@ struct VZVirtualMachineInstance: Sendable {
         try self.init(group: group, config: config, logger: logger)
     }
 
-    init(group: MultiThreadedEventLoopGroup, config: Configuration, logger: Logger?) throws {
+    init(group: EventLoopGroup?, config: Configuration, logger: Logger?) throws {
+        if let group {
+            self.ownsGroup = false
+            self.group = group
+        } else {
+            self.ownsGroup = true
+            self.group = MultiThreadedEventLoopGroup(numberOfThreads: System.coreCount)
+        }
+
         self.config = config
-        self.group = group
         self.lock = .init(VendedConnections())
         self.queue = DispatchQueue(label: "com.apple.containerization.vzvm.\(UUID().uuidString)")
         self.mounts = try config.mountAttachments()
@@ -160,7 +168,10 @@ extension VZVirtualMachineInstance: VirtualMachineInstance {
             }
             connections.agents.removeAll()
 
-            try await self.group.shutdownGracefully()
+            if self.ownsGroup {
+                try await self.group.shutdownGracefully()
+            }
+
             try await self.vm.stop(queue: self.queue)
         }
     }

Sources/Containerization/VZVirtualMachineManager.swift

@@ -19,6 +19,7 @@ import ContainerizationError
 import ContainerizationOCI
 import Foundation
 import Logging
+import NIOCore
 
 /// A virtualization.framework backed `VirtualMachineManager` implementation.
 public struct VZVirtualMachineManager: VirtualMachineManager {
@@ -26,6 +27,7 @@ public struct VZVirtualMachineManager: VirtualMachineManager {
     private let initialFilesystem: Mount
     private let rosetta: Bool
     private let nestedVirtualization: Bool
+    private let group: EventLoopGroup?
     private let logger: Logger?
 
     public init(
@@ -33,12 +35,14 @@ public struct VZVirtualMachineManager: VirtualMachineManager {
         initialFilesystem: Mount,
         rosetta: Bool = false,
         nestedVirtualization: Bool = false,
+        group: EventLoopGroup? = nil,
         logger: Logger? = nil
     ) {
         self.kernel = kernel
         self.initialFilesystem = initialFilesystem
         self.rosetta = rosetta
         self.nestedVirtualization = nestedVirtualization
+        self.group = group
         self.logger = logger
     }
 
@@ -49,6 +53,7 @@ public struct VZVirtualMachineManager: VirtualMachineManager {
         let useNestedVirtualization = vmConfig.nestedVirtualization || self.nestedVirtualization
 
         return try VZVirtualMachineInstance(
+            group: self.group,
             logger: self.logger,
             with: { instanceConfig in
                 instanceConfig.cpus = vmConfig.cpus

Sources/Containerization/Vminitd.swift

@@ -19,6 +19,7 @@ import ContainerizationOCI
 import ContainerizationOS
 import Foundation
 import GRPC
+import NIOCore
 import NIOPosix
 
 /// A remote connection into the vminitd Linux guest agent via a port (vsock).
@@ -35,7 +36,7 @@ public struct Vminitd: Sendable {
         self.client = client
     }
 
-    public init(connection: FileHandle, group: MultiThreadedEventLoopGroup) {
+    public init(connection: FileHandle, group: EventLoopGroup) {
         self.client = .init(connection: connection, group: group)
     }
 
@@ -450,7 +451,7 @@ extension Hosts {
 }
 
 extension Vminitd.Client {
-    public init(socket: String, group: MultiThreadedEventLoopGroup) {
+    public init(socket: String, group: EventLoopGroup) {
         var config = ClientConnection.Configuration.default(
             target: .unixDomainSocket(socket),
             eventLoopGroup: group
@@ -461,7 +462,7 @@ extension Vminitd.Client {
         self = .init(channel: ClientConnection(configuration: config))
     }
 
-    public init(connection: FileHandle, group: MultiThreadedEventLoopGroup) {
+    public init(connection: FileHandle, group: EventLoopGroup) {
         var config = ClientConnection.Configuration.default(
             target: .connectedSocket(connection.fileDescriptor),
             eventLoopGroup: group

Sources/Integration/Suite.swift

@@ -23,6 +23,7 @@ import ContainerizationOS
 import Foundation
 import Logging
 import NIOCore
+import NIOPosix
 import Synchronization
 
 actor UnpackCoordinator {
@@ -159,6 +160,8 @@ struct IntegrationSuite: AsyncParsableCommand {
             .appendingPathComponent(name)
     }
 
+    static let eventLoop = MultiThreadedEventLoopGroup(numberOfThreads: System.coreCount)
+
     func bootstrap(_ testID: String) async throws -> (rootfs: Containerization.Mount, vmm: VirtualMachineManager, image: Containerization.Image, bootlog: URL) {
         let reference = "ghcr.io/linuxcontainers/alpine:3.20"
         let store = Self.imageStore
@@ -221,6 +224,7 @@ struct IntegrationSuite: AsyncParsableCommand {
             VZVirtualMachineManager(
                 kernel: testKernel,
                 initialFilesystem: initfs,
+                group: Self.eventLoop
             ),
             image,
             bootlogURL